St. Petersburg, Russia — Microsoft Corp. said the 12th alleged member of a Russian spy ring operating in the U.S. was an employee at the company's Redmond, Wash., headquarters.

The man, a Russian citizen in his early 20s named Alexey Karetnikov, worked for Microsoft as a software tester for about nine months, a spokeswoman for Microsoft in Moscow, who declined to be identified in line with company rules, said by e-mail today.

Russia's Foreign Ministry declined to comment when contacted by Bloomberg.